Using a Web service data source (Obsolete) – PB Docs 2021

Presentation style
requirement

You can use a Web service as the data source for a DataWindow
having any of the following DataWindow presentation styles:

Support for a Web service data source is not available for
RichText and OLE presentation styles.

Using the DataWindow
wizard

After you select a supported DataWindow presentation style from
the DataWindow tab of the New dialog box, you select a data source for
the DataWindow.

When you select Web Service as the data source and click Next, the
DataWindow wizard opens a page that prompts you to select a WSDL file.
The file you select should be in a publicly accessible location for all
members of the development team. You can enter the URL to a WSDL, ASMX,
or XML file, or you can browse a mapped drive for these types of
files.

The Choose WSDL File page of the DataWindow wizard also lets you
name the assembly file that the wizard will create. The assembly file
serves as an interface between the DataWindow and the Web service. If
you do not name the assembly file, the wizard will select a name for you
based on the name of the WSDL file entry.

The next step to access a Web service data source is to select a
service described in the WSDL, and then one of its public methods. You
must then select a parameter for the DataWindow to use as the result set
for the method.

A DataWindow typically obtains its data from an array of
structures. Because a Web service method can pass an array of structures
in one of its arguments rather than in a return value, the wizard
prompts you to select one of the method’s arguments or its return value
as the designated result set for the method. If you want data for a
single row and column only, you can select a parameter that has a simple
datatype. You can also select a parameter that is an array of simple
datatypes rather than an array of structures.

You complete the wizard as you would when using any other type of
data source for your DataWindow. After you complete the wizard, the
DataWindow displays in the DataWindow painter. However, there is no
equivalent to the SQL painter for a DataWindow with a Web service data
source. For this type of DataWindow, you cannot select Design>Data
Source from the DataWindow painter menu to change selected columns or
modify the DataWindow syntax.

For information on rebuilding an assembly generated by the
DataWindow wizard, see Regenerating an
assembly.

Datatype mappings

The following table lists .NET datatypes and the DataWindow
datatypes to which they map when you use a .NET Web service as a data
source. Arrays are also supported for these datatypes except for
System.Byte.

The DataWindow can also use a Web service data source that has
structures for parameters, as long as the structures are composed of the
simple datatypes that can be mapped to DataWindow datatypes. An array of
structures can be mapped to n rows with x columns where n is the size of
the array and x is the number of members in the structure. Nested
structures are not supported.

Using parameters by
reference

For a Web service that you create from a PowerBuilder nonvisual
object, a result set must be passed by reference, but it cannot be
passed in a method return value. You must use a method argument to pass
the result set and then select that argument in any DataWindow object
that uses the method as its data source.

A parameter passed by reference is a bidirectional [IN,OUT]
parameter by definition. The Web Service DataWindow wizard lets you
select a Web service method [OUT] or [IN,OUT] parameter, instead of the
method return value, to pass a result set to a DataWindow object.
However, the parameter you select cannot be used for both a return value
and a retrieval argument by the same DataWindow object.

Database-related functions and
events

In the Web Service DataWindow, some database or
transaction-related functions and events are not supported and
meaningless because the Web Service DataWindow has no direct relation to
the database. The following functions cannot be used with the Web
Service DataWindow: GetSQLPreview, GetSQLSelect, SetSQLPreview,
SetSQLSelect, SetTrans, and SetTransObject.

The DBError event is also not supported for the Web Service
DataWindow. Instead, you can use the WSError error event to handle
errors during retrieve, insert, or update operations.

Using the WSConnection
object

Some Web services support or require a user ID and password, and
other session-related properties like firewall settings. The
WSConnection object can provide this information for your DataWindow
connections.

You use an instance of the WSConnection object to connect to a Web
service by calling the SetWSObject method.

The following code instantiates a WSConnection object with
user-related and authentication information, then sets the object as the
connection object for a Web service data source:

For more information about setting properties for a Web service
connection, see the section called “WSConnection object (Obsolete)” in Objects and Controls and the section called “SetWSObject (Obsolete)” in DataWindow Reference.

For more information about updating the database with a Web
service DataWindow, see Using a Web service to
update the database.